It’s ironic that the coldest, darkest part of the year is when Americans celebrate their cheeriest holidays. For many, the weather between Thanksgiving and New Year’s says anything but “the most wonderful time of the year”—no matter what the Andy Williams song claims.
For some people, the change in season brings more than just shivers. About six percent of the United States population suffers from seasonal affective disorder (SAD), a subtype of depression that occurs primarily in the fall and winter months. The symptoms are almost identical to the symptoms of major depressive disorder—causing sadness, feelings of hopelessness, and excessive sleep. The difference with SAD is that symptoms fade away when spring and summer come around.
The exact cause of SAD is unclear, but researchers have noticed that people with the disorder exhibit a few characteristics:
A drop in serotonin, a brain chemical associated with mood
An overproduction of melatonin, a hormone that regulates sleep
And insufficient vitamin D levels, which can be caused by a lack of sunlight.
Light Therapy: How It Helps Seasonal Depression + What to Look For
The main way to treat seasonal affective disorder is something called light therapy, which attempts to compensate for the lack of natural sunlight during the winter months. Decades of research have found that light therapy can improve symptoms for about 60 percent of patients, according to UpToDate.
Here’s how it works, according to Harvard Medical School: The bright light stimulates the retina, the back part of the eyeball that sends messages to the brain via the optic nerve. This activates the hypothalamus in the brain, which helps control your circadian rhythms. This helps fight the lethargy and excessive fatigue associated with seasonal depression.
But don’t turn on your desk lamp and expect to notice an improvement. Light therapy requires special lights, called “light boxes,” that are around 20 times brighter than your standard indoor light, according to the National Institute of Mental Health.
A good light box should:
Provide 10,000 lux (which is a measurement of light intensity)
Filter out UV wavelengths
And emit cool-white fluorescent light.
You should also consider how and when you plan to use it. Different models can be attached to walls or propped up on tables. Think of a time during your morning routine when you might be in one spot for a stretch of at least 20 minutes, like drinking coffee at your dining table or applying makeup in front of the bathroom mirror. Pick a light box model that works with those locations.
An exciting and more recent option is a dawn simulation light box. These light boxes often double as alarm clocks. Half an hour before your alarm goes off, these light boxes begin emitting a dim light, and the brightness gradually increases until it reaches full brightness to mimic sunrise by the time your alarm goes off. Many offer soothing sound options as well, so you can start your day with faux sunlight *and* birds chirping.
If you need help choosing a light box, don’t be afraid to get in contact with your doctor. They may have recommendations, as well as other tips for soothing seasonal affective disorder.